Sprag.



J. H. LAVERS.

1 SPRAG. APPLICATION FILED JUNE 28,1912.

1,085,691 Patented Feb.3,1914.

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lumai/HO@ wbb/Leases' /w' @M j/W/M/Lm Joann. Levens, or KEARSARGE,MICHIGAN.

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Specication of Letters Patent.

Patented Feb. 3, 1914.

Application filed June 28', 1912. Serial No. 706,460. i

To all who-mit may concern: p

Be it known'that I, JOHN H. LAvEns, a citizen of the United States,vresiding at Kearsarge, in the countyjofHoughton and State of Michigan,have invented certain new `and useful Improvements in Sprags; and I dohereby declare the following to be a full, clear, and exact descriptionof the invention, such as will enable others skilled in the arttowhichvit appertains to `make anduse the same.

This invention relates to columns used in mines, drifts and othersimilar places in connection with rock drills;.and it consists in thenovel construction and combination of the parts hereinafter `fullydescribed and claimed. y v

In the drawings, Figure 1 is a front view ofa column` constructedaccording to this invention, and showing its lower, part partially insection. Fig. 2 is a plan view of the jack. l

The main portion of the column consists of a tubular metallic columnhaving a reinforcing band or collar 3 secured in its lower `endportion,`by shrinking or otherwise. The

column 2 and its band 3 have a notch 4 at their lower ends. A cap 5 issecured to the top of the column for engaging with the roof.' A onepiece jack is provided, and thisjack has a socket 7 at its middle part.Thissocket has a shoulder 8 at its bottom, for the bottom-of thecolumn 2and the collar 3 to rest on, `and it has a lug 9 which engages with thenotch 4 so that the column cannotrevolve in the socket. The end portionsof the jack have tapering sockets 10 in which screwthreaded sleeves ornuts 11 are secured. Adjusting screws 12 are provided,

and work in the nuts 11. Holes are provided in the socket 7 and in thecolumn, and a pin 14 is slipped into these holes so that the column andthejack can be moved about without becoming separated. The screws 12have hemispherical ends 16 which rest in shoes 17 whichhave socketsshaped to re-y ceive them. The shoes` 17 rest on the iioor or ground,`and adapt themselves to slight irregularities of surface. The screws aretightened up until the column is secured in place. An arm 2O forsupporting a rockdrill is clamped to the column 2, and this arm restsupon a collar 21 which is also clamped on the column. The collar can beset at any desired height above the ground, and the supporting arm canbe turned around from time to time to suit the drill, and can be heldsecurely in various positions as the column is prevented from revolvingby the lug in its socket.

What I claim is:

In a sprag, the combination, with a base having a cylindrical socket, ofa tubular column the lower end portion of which engages slidably withthe said socket, a reinforcing band permanent-ly secured to the columninside its bottom end portion and resting with it on the bottom ofthesocket, said parts being provided with means which normally prevent thecolumn from revolving inthe socket, and a removable retaining pinpassing crosswise through holes in the column and socket.

In testimony whereof l have afiixed my signature in the presence of twowitnesses.

JOHN H. LAVERS.

Witnesses:

WM. J. DANIELL, A. G. GULLBERG.

